In digital packet radio transceiver networks, there are several schemes for coordinating multiple radios to access a shared radio channel. One such scheme is time-division-multiple-access (TDMA). FIG. 1. In TDMA, each transmitting station is assigned a time slot within a repeating time frame, called a dwell period, during which only that station is allowed to transmit. In a star configured wireless network, a central base station is surrounded by one or more remote stations. As opposed to a peer-to-peer network configuration, remote stations are only allowed to communicate with the base station and not to each other. The sequence of transmission slots begins with a transmission by the base station which is received by all remote stations and followed by an individual transmission slot for each remote station. FIG. 2.
Digital communications networks often provide a facility for retransmitting defective or errant data messages. One common form of such error handling is automatic repeat-request, or ARQ. In ARQ, the transmitting station listens after every transmitted message for an acknowledgment (ACK) message from its recipient. If the originating station fails to receive the ACK message, the originally transmitted message is sent again, repeating until either the ACK is received or a predetermined number of attempts have been made, in which case the message is discarded.